Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on May 23, 2015, 04:14:45 am

Title: Lupus in Fabula - Laney Klipp 60 - What is doing V2 ??
Post by: kagliostro on May 23, 2015, 04:14:45 am

Talking with DummyLoad about the Laney 60 he has on the bench, I was thinking to have under hand the schematic (which however it is not)

the schematic is of a Laney Klipp 60, not the model DummyLoad has

firstly I didn't noticed it ...... but give also you a look to V2 ........ which is the path of the signal ?? and what about the function of V2 ??

(http://www.prowessamplifiers.com/schematics/images/klipp_60.jpg)

I'm (newly, it happens often due to my poor knowledge) confused  :dontknow: :w2: :dontknow:

Are you able to follow the signal path and understand the function of V2 on the amp ?

Many Many Thanks

K

Title: Re: Lupus in Fabula - Laney Klipp 60 - Wat is doing V2 ??
Post by: jazbo8 on May 23, 2015, 04:47:52 am

It's an odd design choice, but it is basically an un-balanced LTP, i.e., the input signal is taken from the common cathode node, since Ip=Ik, the output at the plate Vo = Ip x Rp or Ik x Rp.

Title: Re: Lupus in Fabula - Laney Klipp 60 - What is doing V2 ??
Post by: kagliostro on May 23, 2015, 05:55:17 am

Thanks Jazbo8

I was thinking to something like you say (a PI)

but I'm not understanding at all the reason for such a "gain" (??) stage

also, there is something that looks like an SPDT switch that seems to be there as to bypass V2 (http://www.diyitalia.eu/forum/images/smilies/Trilly-18-39.gif)   (http://www.diyitalia.eu/forum/images/smilies/Trilly-18-39.gif)

This give the idea that V2 has an effect on the signal that is possible to insert or disinsert, but which  :w2:

Quote

EDIT:


Also the 22k || 15uf that is connected between the plate of V2a and ground didn't help to understand

on the contrary, it confuses further

Again Thanks

Franco

Title: Re: Lupus in Fabula - Laney Klipp 60 - Wat is doing V2 ??
Post by: VMS on May 23, 2015, 01:20:18 pm

Quote from: kagliostro on May 23, 2015, 05:55:17 am

but I'm not understanding at all the reason for such a "gain" (??) stage

Franco

Preamp distortion.

This Faustone valve klipper is based on that circuit:

http://faustone.com/valve_klipper.html (http://faustone.com/valve_klipper.html)

Title: Re: Lupus in Fabula - Laney Klipp 60 - What is doing V2 ??
Post by: kagliostro on May 23, 2015, 03:04:03 pm

Many thanks VMS

I've never heard of it before

Now, searching with the name of the pedal, I've also find a sample of the pedal tried with some amps


https://www.youtube.com/watch?v=BWTXbxSNWQg (https://www.youtube.com/watch?v=BWTXbxSNWQg)

Thanks

Franco